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// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
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//
//   http://www.apache.org/licenses/LICENSE-2.0
//
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package org.apache.doris.nereids.trees.expressions.functions.scalar;

import org.apache.doris.catalog.FunctionSignature;
import org.apache.doris.nereids.trees.expressions.PreferPushDownProject;
import org.apache.doris.nereids.trees.expressions.functions.ExplicitlyCastableSignature;
import org.apache.doris.nereids.types.LambdaType;
import org.apache.doris.nereids.types.coercion.AnyDataType;

import com.google.common.collect.ImmutableList;

import java.util.List;

/**
 * Interface of HighOrderFunction, provide default FunctionSignature of LambdaType argument
 */
public interface HighOrderFunction extends ExplicitlyCastableSignature, PreferPushDownProject {
    @Override
    default List<FunctionSignature> getSignatures() {
        return new ImmutableList.Builder<FunctionSignature>()
                .addAll(getImplSignature())
                .add(FunctionSignature.ret(AnyDataType.INSTANCE_WITHOUT_INDEX).args(LambdaType.INSTANCE))
                .build();
    }

    List<FunctionSignature> getImplSignature();
}
